effects of ephedrine (8). The effects of aspirin on ephedrine appears to occur primarily in obese,
but not lean individuals (12,13).
The combination of ephedrine, caffeine and aspirin has become known as the ECA stack in
sports nutrition. It can be consumed in synthetic form or by taking the herbal equivalents of
MaHuang (herbal ephedrine), kola nut or guarana (herbal caffeine), and white willow bark (a
herbal form of aspirin). At least one popular author feels that white willow bark is not a suitable
substitute for aspirin (19).
Important note on the ECA stack
The ECA stack is a potent stimulant for the central nervous system (CNS) making it a
potentially dangerous compound, especially if used indiscriminately. There are an increasing
number of individuals reporting negative responses to ephedrine, and a handful of deaths have
been attributed to the combination of ECA. While details of all of these negative reactions are
not available, there is an increasing use of herbal ephedrine (MaHuang) in a variety of nutritional
supplements. The risk of overdose, especially in herbal products which are not standardized, is a
possibility. In general, the studies show good tolerance among subjects taking the ECA stack at
the recommended dose (11,14,20).
Under no circumstances should the recommended dose of ECA be exceeded. Any negative
reactions beyond the normal stimulant effect indicates that the ECA stack should not be taken.
Additionally, as a potent CNS stimulant, individuals with any type of preexisting heart condition
should not use this combination of compounds. Also, individuals with thyroid or prostate
problems should not use ECA. Individuals taking monoamine oxidase inhibitors (MAOI) should
not use ECA.
Dosing and the ECA stack
Most of the available research points to the following combination of doses as optimal for
the ECA stack (9,12-14,20,21):
ephedrine: 20 milligrams
caffeine: 200 milligrams (the amount of caffeine should be 10 times the amount of ephedrine)
aspirin: 80-325 milligrams
There is some debate over the amount of aspirin necessary to potentiate the effects of
caffeine and ephedrine. While 300 mg has been used in research (13,14), this much aspirin three
times daily can have potentially negative effects on the gastrointestinal tract, and can not be
recommended. Some popular authors have suggested as little as 80 milligrams for positive
effects (19).
This ECA stack is typically taken three times daily, with one dose in the morning, a second
dose four to five hours later, and a third dose taken in the afternoon no later than 4 pm (to avoid
problems with insomnia). Individuals who are sensitive to the side effects of ECA should begin